This research initiates an intensive investigation into the role of carbohydrates as receptors and binding agents on cell plasma membranes and on glycolipid molecules. Its primary ultimate objective is to understand cell-cell interactions and to relate these to cancer and to the immune response. More specifically its aims are to understand possible interactions at the plasma membrane surface involving carbohydrates and to distinguish between various mechanisms for molecular, ion, and cell binding. Cell-surface carbohydrates generally occur as branched oligosaccharide chains containing particular sugars such as N-acetyl neuraminic acid (sialic acid), N-acetyl glucosaaine, L-fucose, D-galactose, and D-mannose. Nuclear magnetic resonance (NMR) and lanthanide ions will be used as sensitive probes of the interactions of these saccharides with themselves and with ions, polypeptides, proteins, and lipids. Relevant disaccharide and oligosaccharide chains, usually terminating in sialic acid, will be obtained in sufficient quantities by extraction from animal organs serum glycoproteins, etc., and will be investigated to observe expected tertiary structure effects upon their ossociation with other saccharides, ions, proteins, etc. The interactions of receptor carbohydrates in model membranes (liposomes) with incorporated glycoproteins and glycolipids will be investigated, and the effect of these interactions on membrane properties will be observed. Alterations after treatment with glycosidases and mitogens will be noted. 13C NMR will be applied to study erythrocyte ghosts in more detail, particularly with respect to the membrane carbohydrates and their interactions. The procedures used and information obtained on these systems will then be applied to the investigation of the plasma membranes of other cells.